1. Field of the Invention
The present invention relates to a capped rivet with two parts: a cap part (cap, for short) and a rivet part. The cap has an exposed topside and an inside, and the rivet part has a rivet shank and a rivet flange. The rivet shank extends away from the inside of the cap, and the rivet flange extends transverse to the axis of the rivet shank and is firmly attached to the cap. The invention also relates to an attachable element comprising a capped rivet of this kind and to a carrier material to which the attachable element is connected.
Capped rivets as introduced above may have the form of decorative elements that are attachable to a sheet-like carrier material, for example to clothing garments and carrying bags. Furthermore, capped rivets of this kind may also be used for attaching snap-button closure elements to a sheet-like carrier material. In this case, the rivet shank is passed through the carrier material and then shaped to form the attachment of the capped rivet. To protect the carrier material or to attach a snap-button closure part, it is possible to first slide a counterpart such as a lug or a ball forming the snap-button closure part onto the rivet shank after it has been passed through the carrier material and then clamp the counterpart against the carrier material by deforming the rivet shank.
The deformation of the rivet shank required for fastening the capped rivet is usually performed by a rivet-installation machine comprising a riveting tool that presses against the exposed topside of the cap and pushes the rivet shank through the carrier material against a tool that holds the counterpart.
2. Description of the Related Art
A known capped rivet used for the installation of snap-button closure parts is shown in FIG. 5. This capped rivet has a cap 100 and a rivet part 110 consisting of a rivet shank 112 and a rivet flange 114. To attach the rivet part to the cap, the outer rim 106 of the cap 100 is bent downward and inward to reach around and below the outer rim of the rivet flange 114. To install the snap-button closure part, a riveting tool pushes against the exposed topside 102 of the cap 100 and forces the capped rivet through the carrier material and against a counteracting tool that bends the free end 112 of the rivet shank outwards and upwards so that the carrier material is clamped against a clamping surface 116 at the underside of the rivet flange 114. In this process, the pressure force of the installation tool may have the effect of deforming the cap 100, thereby damaging the appearance of the capped rivet.
To solve the aforementioned problem, the capped rivet of FIG. 6 has been proposed. In addition to the rivet shank 112 and the rivet flange 114, the rivet part 110 of this capped rivet has two supporting portions 120 that are arranged between the rivet shank 112 and the cap 100 and extend approximately parallel to the inside of the cap. The supporting portions 120 are formed by cutting out and folding back two sections of the rivet flange along fold lines running between the rivet shank 112 and two windows 118 in the rivet flange that are formed as a result of this process. The supporting portions 120 form a thrust-bearing surface to counteract the effect of the insertion tool of deflecting the cap 100 towards the rivet shank 112 and thus to prevent the undesirable deformation of the cap 100.
To further stabilize the cap, a capped rivet of the kind shown in FIG. 5 is proposed in DE 196 38 450 where one of the supporting portions is folded over the other in such a manner that the topside of one supporting part is in at least partially overlapping contact with the bottom side of the other.
This arrangement provides a reliable means of preventing the undesirable deformation of the cap during the rivet-installation process. However, the known capped rivet has proven to be unsuitable for the attachment of watertight snap buttons because the windows that the supporting portions leave in the rivet flange form a leakage spot. In addition, the process of forming the supporting portions by folding back sections of the rivet flange and thereby opening up corresponding windows in the rivet flange has proven to be a problem, particularly in the case of capped rivets with flanges that have a stepped profile rather than a plane surface, e.g., in spring pin rivets. Finally, the known way of stabilizing the cap cannot be used if the diameter of the rivet flange is only insignificantly larger than the diameter of the rivet shank.